Concrete anchoring insert and method of preventing concrete seepage therein



I Nov. 9, 1965 R. H. JENKINS 3,216,171

CONCRETE ANCHOR INSERT AND METHOD OF PREVENTING CON ETE SEEPAGE THEREIN Filed May 14, 1962 3 Sheets-Sheet l ATT).

Nov. 9, 1965 R. H. JENKINS 3,216,171

CONCRETE ANCHORING INSERT AND METHOD OF PREVENTING CONCRETE SEEPAGE THEREIN Filed May 14, 1962 3 Sheets-Sheet 2 3 M INVENTOR.

' ROBE PT H. JENKINS Nov. 9, 1965 R. H. JENKINS 3,216,171

CONCRETE ANCHORING INSERT AND METHOD OF PREVENTING CONCRETE SEEPAGE THEREIN Filed May 14, 1962 3 Sheets-Sheet 3 E fJ- 111M" ll 5? HIP m2 All //V VE'N TOR ROBERT H. JENKINS MM ATTX United States Patent CONCRETE AN CHORING INSERT AND METH- 0]) OF PREVENTING CONCRETE SEEPAGE THEREIN Robert H. Jenkins, Piedmont, Calif., assignor to Superior Concrete Accessories, Inc., Franklin Park, Ill., a corporation of Delaware Filed May 14, 1962, Ser. No. 194,420 8 Claims. (Cl. 52741) The improved anchoring insert comprising the present invention is illustrated herein in connection with a concrete wall slab of the tilt-up variety. Such insert, which is formed for the most part of heavy wire or rod stock, is adapted to be embedded in one corner portion of the wall slab during formation of the latter and serves, with similar inserts in the other corner portions of the slab, and after hardening of the concrete, as a medium whereby the slab may be detachably connected to a crane or like hoisting mechanism to the end that the slab may be first raised while in a horizontal position and then tilted into a vertical position next to a concrete floor slab in connection with the erection of a building. The invention is, however, not to be limited to such particular use and a wire-formed anchoring insert which is constructed according to the principles of the present invention may find use wherever an anchor point is required in a concrete structure undergoing formation. Irrespective, however, of the particular use to which the invention may be put, the essential features of the invention are at all times preserved.

Briefly, and as disclosed in United States Patent No. 2,794,336, granted on June 4, 1957, to Harry G. Ballou, and entitled Lag Screw Anchoring Insert for a Concrete Slab, an insert of the general character with which the present invention is concerned includes at its principal components a nut-like, wire-formed helix to which there is welded a wire-supporting structure presenting a series of supporting legs whereby the helix may be supported from a foundation surface so that it assumes an elevated position above such foundation surface, the entire assembly assuming the general form of a chair. When the slab or structure-forming concrete is poured, the chair-like insert becomes embedded in the concrete and the helix assumes a position at a right angle to the upper surface of the poured slab and with its upper end substantially flush with said surface to the end that it may threadedly receive therein the shank portion of a lag screw or other attaching device. In order to maintain the threaded bore of the helix free or clear of concrete to the end that it will be able to receive therein the shank portion of the lag screw, it has heretofore been the practice to thread a headless slotted concrete-displacing bolt into the helix and allow the same to remain therein during concrete pouring and hardening operations. The fact that the bolt is headless enables strickling operations to be performed on the concrete slab, utilizing a suitable screed and strickle bar as is customary in slab levelling operations. After the concrete has hardened, the headless slotted bolt is unscrewed from the helix, utilizing a screwdriver or other suitable turning tool and, after such removal, the bore of the helix is open and, for the most part, free from concrete so that it is capable of receiving therein the shank portion of the lag screw or other attaching device.

The above briefly outlined procedure is possessed of certain inherent limitations, principal among which is the fact that the initial insertion of the headless dummy bolt into the helix and its subsequent removal therefrom is time consuming. Additionally, due to the wide tolerances prevalent in connection with the manufacture of lag screws, no given headless dummy bolt can be expected 3 ,2 16,1 71 Patented Nov. 9, 1965 ICC to displace the exact amount of concrete necessary to clear a path for subsequent entry of the shank portion of the lag screw. Small amounts of concrete may seep through the coil turns of the helix before being blocked by the dummy bolt and present an obstacle to subsequent receptionof the shank portion of the lag screw. Thus, the removal of the dummy bolt from the helix may be a difiicult operation due to the fact that it has become concrete-bound. Also, the subsequent threading of the lag screw into the helix, as well as the unthreading thereof for removal purposes, may not be easily accomplished.

The present invention is designed to overcome the above-noted limitations that are attendant upon prior methods of excluding the seepage of concrete into and about helically wound wire anchoring inserts and, toward this end, the invention contemplates the provision of a novel method which embodies the use of an insert which, in addition to the usual wire helix and supporting structure therefor, includes a novel form of concrete displacement member which is designed for reception in and about the helix of the insert prior to concrete pouring operations and is operable during concrete pouring and hardening operations to displace a volume of concrete which is appreciably greater than has heretofore been displaced by the conventional slotted headless dummy bolt, to the end that a subsequently applied lag screw may, without obstruction, find easy access to the interior of the helix, as well as being capable of easy removal from its threaded engagement with the helix when desired.

The provision of a method and; and an insert of the character briefly outlined above being among the principal objects of the invention, it is a further object to provide such a method and insert wherein the displacement member is expendable in that it may be left in position within and about the helix during and after concrete pouring operations and which, moreover, need not be removed from the helix during application to the latter of the lag screw, the character of the displacement member being such that it will collapse or disintegrate, so to speak, and by its disintegration, make room for the lag screw as the latter is threaded into the helix. After such disintegration, subsequent unthreading and removal of the lag screw from the helix will present no problem.

Another object of the invention is to provide an anchoring insert of this type wherein the wire helix assumes a position below the uppermost level of the supporting structure therefor so that, ordinarily, there would be a concrete-filled void immediately above the helix which would block access to the threaded bore of the helix by the lag screw, and in which the displacement member is of a composite nature and consists of a lower plug which is in part receivable within the threaded bore of the helix and an upper cap part receivable above the bore for concrete displacement purposes so that the aforementioned void will remain clear of concrete.

A still further object of the invention is to provide in an anchoring insert of the type under consideration a composite displacement member in which the lower plug part includes an upper cylindrical section which is of relatively small diameter and serves, when the member is in position in an installation, to fill the threaded bore of the helix, and a lower cylindrical section which is of relatively large diameter, underlies the helix altogether, and serves to displace concrete beneath the latter during concrete pouring operations so that when the lag screw is threaded through the bore it may extend into and have clearance within the void thus created beneath the helix.

Still another object of the invention is to provide in connection with an anchoring insert of the type under consideration a displacement member in which the lower plug part has an annular upwardly facing shoulder thereon which is contoured precisely to fit the lower end of the helix with which it mates, and in which the upper cap part similarly has an annular downwardly facing shoulder thereon which is contoured precisely to fit the upper end of the helix with which it mates.

Numerous other objects and advantages of the invention, not at this time enumerated, will become readily apparent as the nature of the invention is better understood.

In the accompanying three sheets of drawings forming a part of this specification, two illustrative embodiments of the invention and one illustrative environment therefor have been disclosed, purely by way of example and not by way of limitation.

In these drawings:

FIG. 1 is an exploded side elevational view of an anchoring insert and concrete displacement member therefor, both being constructed according to certain principles of the present invention;

FIG. 2 is a side elevational view of the assembled structure of FIG. 1;

FIG. 2a is an enlarged fragmentary sectional view taken axially through portions of the insert and the displacement member;

FIG. 3 is a top plan view of the structure shown in FIG. 2;

FIG. 4 is a fragmentary vertical sectional view taken through a tilt-up type concrete wall slab in the vicinity of one of the embedded insert assemblies and showing the latter after it has been connected to a harness on an overhead hoist;

FIG. 5 is an enlarged perspective view of the plug part of the concrete displacement member;

FIG. 6 is an enlarged perspective view of the cap part of the concrete displacement member;

FIG. 7 is an exploded side elevational view, similar to FIG. 1 but showing a modified form of composite two-part concrete displacement member;

FIG. 8 is a side elevational view of the assembled structure of FIG. 7;

FIG. 9 is a perspective view of one of the two parts of the composite concrete displacement member of FIG. 7; and 7 FIG. 10 is a perspective view of the other part of the composite displacement member of FIG. 7.

Referring now to the drawings in detail, the anchoring inserts which are disclosed therein constitute preferred forms or embodiments of the invention. One of these embodiments is shown in FIGS. 1 to 6, inclusive, and it is designated by the reference numeral 10. This insert is adapted with similar inserts (not shown) to be embedded in a tilt-up type concrete wall slab, such as the slab fragmentarily shown at 12 in FIG. 4 and to form with such inserts a medium whereby the slab may be detachably connected to a crane or other overhead hoist to the end that it may be raised and then tilted into a vertical position next to a concrete floor slab 14 in connection with the construction of a building.

The specific manner in which the wall slab 12 is initially formed and subsequently raised into proper position utilizing anchoring inserts which function generally in the manner of the present insert 10, is illustrated and described in aforementioned Patent No. 2,794,336, and need not be discussed in detail herein, suffice it to say that the wall slab is formed by pouring wet concrete over the surface of a previously formed floor slab, a fragment of which is shown at 14. A layer or film of non-adhesive material is applied to the top surface of the concrete floor slab 14 so that the wall slab 12, after hardening of the concrete, may readily be lifted from the floor slab for placement or positioning purposes. The floor sla-b 14 rests on a fill or foundation 16 at the site where the building is undergoing erection. Prior to pouring of the concrete of the wall slab 12,

the insert 10 and its associated similar inserts are placed over the hardened concrete of the floor slab 14, preferably at the corner regions thereof, and the concrete for the wall slab is then poured over the non-adhesive layer and within the usual rectangular concrete form structure (not shown) in order to form the wall slab 12. After such concrete has hardened, the wall slab 12 with the anchoring inserts embedded therein is in readiness to be raised and then tilted into a vertical position next to the floor sl-a-b as hereinafter described.

The anchoring insert 10 is of a composite nature and comprises three separate parts, namely, a metal insert proper 20, a lower displacement plug 22, and an upper displacement cap 24. The plug 22 and the cap 24 are formed of a non-elastic, highly and easily compressible, composition material for reasons that will be made clear presently and the function of these members is to form displacement areas or regions in the immediate vicinity of the insert proper 211 into which concrete is prevented from flowing during concrete pouring operations so that these regions may constitute clearance regions for reception therein of the shank portion of a lag screw as will also be made clear subsequently.

The insert proper 20 is a unitary structure and for the purpose of the following description, it will be considered as being embedded in one corner region of the wall slab 12 while the latter is horizontally positioned over the concrete floor slab 14. As its principal components, the insert proper 26 includes a nut-like wire helix 26 and a series of four generally L-shaped legs 28 which are separately formed from the helix but which are welded thereto so that the helix and legs constitute a unitary composite structure. The wire helix 26 is tightly wound, which is to say that adjacent convolutions thereof abut against each other. It extends vertically and the upper end thereof is disposed slightly beneath the upper side surface 30 of the horizontally positioned wall slab 12, while the lower end thereof is disposed an appreciable distance above the lower side surface 32 of the wall slab. The interior of the helix 26 defines an internal screw thread which is designed for reception therethrough of the shank portion 34 of a lag screw 36.

The four L-shaped legs 28 are identical in construction and, therefore, a description of one of them will suffice for the others. Each leg includes a substantially straight vertical part 40 and a generally horizontal part 42. The upper regions of the vertical parts 40 are welded as at 44 to the outer portion of the helix 26. The horizontal parts 42 project generally radially outwardly from the helix 26 and not only extend at right angles to one another but have a common median horizontal plane. Said horizontal parts 42 are of irregular configuration and include U-shaped bight portions 46 which afford feet for the legs as a whole and these feet are adapted to be supported upon the aforementioned non-adhesive layer on the upper face 48 of the fioor slab 14 (see FIG. 4).

The legs 28 are formed of medium gauge wire and serve, in connection with the formation of the wall slab 12, to space the helix upwardly from the upper surface 48 of the floor slab 14 and cause the same to assume a vertical position with its upper end disposed slightly below the level at which concrete pouring operations terminate.

The previously mentioned lower displacement plug 22 and the upper displacement cap 24 are provided for the purpose of preventing infiltration of concrete into the interior of the helix 26 and also to provide clearance excess of the internal diameter of the helix. The juncture region between the lower and upper sections 50 and 52 affords an upwardly facing shoulder 54. The longitudinal extent of the lower cylindrical section 50 of the plug 22 is approximately equal to the extent of overhang of the straight vertical part 42 of the four legs 28 below the helix 26 while the longitudinal extent of the upper cylindrical section 52 is slightly greater than the length of the helix 26. The lower displacement plug 22 is adapted to be installed within the confines of the insert proper 20 with the upper cylindrical section 52 substantially filling the helix and projection a slight distance thereabove as shown in FIG. 2, and with the lower cylindrical section 52 substantially filling the space encompassed by the overhanging portions of the four legs 28. In this position of the displacement plug 22, the upwardly facing shoulder 54 abuts against the lower end of the helix coextensively. In order to provide for such coextensive engagement between the shoulder 54 and the lower end of the helix 26, the shoulder is contoured conformably to said lower end of the helix, it being provided with a helical surface having an extent of one helix turn, the surface being provided with a sharp drop-off affording a vertically disposed shoulder 56 (see FIG. 1) which is designed for abutting engagement with the extreme lower end 58 of the wire from which the helix is formed.

The upper displacement cap 24 is of inverted cupshape design, it being cylindrical and having an inverted socket 611 in the lower face thereof. The diameter of the socket is such that it may be received over the upper end of the upper cylindrical section 52 of the lower displacement plug 22 with the rim 62 of the cap seating upon the upper end of the helix 26. Accordingly, the rim 62 is contoured conformably to the upper end of the helix and is provided with a sharp drop-off affording a drop-off shoulder 64 similar to the shoulder 56 and similarly designed for engagement with the extreme upper end 66 of the wire from which the helix is made.

The material from which the upper displacement plug 22 and the displacement cap 24 are formed is highly compressible and is of a non-elastic nature. When compressed or otherwise deformed and the compressional force removed, the material has little, if any, tendency to become restored to its original condition or shape. Various materials may be found suitable for use in the manufacture of the two displacement members 22 and 24 as, for example, pressed aerated talc and various other aerated or cellular chalk-like substances which may be said to disintegrate when subjected to compressional forces. One such material which has been found admirably well-suited for use in the manufacture of the two displacement members is the material known as expanded polystyrene foam, a product manufactured by the Dow Chemical Company. This material is white in color, is of spongy appearance and yet holds its shape well under slight compressional or other distortional forces. However, when subjected to higher compressional or deforming forces it will readily yield to such forces and become deformed to an unusual degree. As an example of its compressibility, a strip of expanded polystyrene having a thickness of one inch may be flattened by moderate pressure to paper-thin proportions. Under deforming pressures which are frictionally applied as, for example, the boring action of a threaded element, such as a lag screw shank or the like, some of the material in the vicinity of the shank will disintegrate by a rubbing action while the remainder of the material will become highly compressed and will fiow along lines of least resistance. After removal of the deforming pressure, the material will have very little tendency to become restored, even in part, to its original condition or shape.

In the installation and use of the anchoring insert 10, the three parts 20, 22 and 24 of the insert are first assembled upon one another before the insert is placed in position upon the upper layer-equipped surface 48 of the floor slab 14. The lower displacement plug 22 is inserted through the helix 26 and overhanging portions of the straight vertical parts 40 of the legs 28 by telescoping or inserting the same upwardly into the insert proper 20 from the underneath side thereof so that the upper cylindrical section 52 of the plug projects into and through the helix 26. Since the diameter of the section 52 is slightly in excess of the internal diameter of the helix 26, this section will fit snugly within the helix and substantially fill the interior of the latter. The lower cylindrical part 50 of the displacement plug 22 will substantially fill the space encompassed by the overhanging portions of the four legs 28. After the displacement plug 22 has been moved upwardly within the insert proper 20 to such an extent that the upwardly facing shoulder 54 engages the lower generally circular end of the helix 26, the displacement plug may be rotated about its vertical axis to bring the shoulder 56 into abutting engagement with the lower end 58 of the wire material from which the helix 26 is formed.

After the displacement plug 22 is thus in position within the insert proper 20, the upper displacement cap 24 is applied. Application is made by telescoping the cap 24 over the upwardly projecting end of the upper cylindrical section 52 of the displacement plug 22 so that the upper end of the plug enters the socket 60 and the rim 62 of the cap seats upon the upper circular end of the helix 26. Thereafter, the cap 24 may be rotated about its vertical axis to bring the shoulder 64 into abutting engagement with the upper end 66 of the wire material from which the helix 26 is formed.

With the lower displacement plug 22 and the upper displacement cap 24 thus in position with respect to the insert proper 20, these two displacement members and the helix 26 are in coaxial alignment and contiguity. The entire anchoring insert is then ready for positioning on the floor slab 14 in the manner previously described for subsequent embedment within the poured concrete of the wall slab 12.

After the wet concrete of the wall slab 12 has been poured, suitable strickling operations, utilizing a screed, are performed upon the upper surface of the concrete and the latter is levelled to coplanar relationship with the upper end of the embedded displacement cap 24. When the concrete of the wall slab 12 has become set, the lag screw 36 is applied to the anchoring insert for attachment thereto of whatever hoisting harness may be deemed expedient. The lag screw 36 may be applied to the insert 10 without necessitating removal of either the displacement cap 24 or of the displacement plug 22. It is merely necessary to apply the pointed end of the shank portion 34 of the lag screw 36 to the upper face of the displacement cap 24 with a moderate degree of pressure and to rotate the lag screw in the usual manner of application so that the lag screw seeks its own thread within the material of the displacement cap 24. As the threading operation proceeds, the shank portion 34 bores it way, so to speak, through the displacement cap, pushing the material of the cap aside and compressing the same against the cylindrical wall 79 (see FIG. 4) of the concrete void surrounding the cap. The end of the lag screw then enters the helix 26 and finds threaded engagement therewith so that continued rotations of the lag screw threads the same through the helix and through the material of the upper cylindrical section 52 of the displacement plug 22. This latter material also is pushed aside and compressed against the generally corrugated or internally threaded inside wall surface of the helix 26, as shown in FIG. 4. Still further rotation of the lag screw 36 causes the lower end region of the lag screw to enter the material of the lower cylindrical section 50 below the helix 26 and displace this material so as to compress it against the cylindrical concrete wall surface 72 of the void created in the concrete by this lower portion of the displacement plug 22.

Due to the high compressibility of the material of which the displacement cap 24 and the displacement plug 22 are formed, there is ample room for displacement of the material in both voids 70 and 72 to an extent sufiicient to permti facile entry of the shank portion 34 of the lag screw 36. Within the helix 26, there also is ample room for such displacement of the material inasmuch as a continuous helical void 74 (see FIG. 2a) surrounds the upper cylindrical section 52 prior to entry of the lag screw into the helix. This void exists by reason of the confined space which is bounded by the outside cylindrical surface of the lower displacement plug and the tangentially disposed Wire turns of the helix. The helix, although being tightly wound, does not completely exclude concrete from seeping into this helical void and, when the shank portion 34 of the lag screw 36 enters the helix, substantially all of the material of the cylindrical portion 52 of the displacement plug 22 is forced into the void 74, thus sealing adjacent coil convolutions against ingress of concrete into this helical void. The material of the displacement member 22 offers to the metal of the shank portion 34 of the lag screw 36 an appreciable coefficient of friction so that, to a certain extent, the material resists sliding contact with the lag screw. Therefore, there will be some crumbling or disintegration of the material, as well as compression thereof, thus further contributing toward a reduction in the total volume of the material.

In order that the wall slab 12 may be hoisted from its horizontal position on the floor slab 14 and then tilted into a vertical position for wall-forming purposes, as previously described, the lag screw 36 passes through the horizontal flange 80 of an angle piece 82 and serves to clamp this angle piece against the upper face 30 of the hardened wall slab 12. The vertical flange 84 is provided with a hole 86 therethrough and receives the shank portion 88 of an eye bolt 90, the latter being operatively connected to one of the cables 92 of the hoisting harness in associated relation with the overhead crane or other hoisting apparatus. The details of the hoisting harness have not been disclosed herein since it forms no part of the present inveniton. An exemplary form of harness is show and described in aforementioned Patent No. 2,794,- 336 and reference may be had to such patent for an understanding of a harness suitable for use in connection with the installation of the present invention.

After the wall slab 412 has been manipulated into its upright position and the necessary installation thereof effected, the lag screw 36 may be removed merely by un threading it from threaded engagement with the helix 2 6. After such removal of the lag screw '36 and the corresponding lag screws for the associated similar anchoring inserts, the harness may be dismantled. The partially disintegrated and compressed material of the two displacement members 22 and 2'4 will remain within the voids which contain them and any other voids may thereafter be filled with grout. Due to the particular material of which the displacement members 22 and 24 are formed, there will be little, if any, resisance to removal of the lag screw which will turn easily in the threaded paths provided for it.

In FIGS. 7 to 10, inclusive, another embodiment of the invention has been illustrated. In this latter embodiment, the composite displacement plug is comprised of two identical parts, including an upper part 100* and a lower part 102, these parts corresponding roughly in their positional relationship and functions to the parts 24 and 22, respectively, previously described in connection with the form of the invention illustrated in FIGS. 1 to 6, inclusive.

The parts 100 and 102 are shown in FIGS. 7 and 8 as being applied to one of the anchor-ing inserts 20 and, since such an insert has been fully described in connection with the form of the invention shown in FIGS. 1 to 6, inclusive, repetition of description has been avoided herein by the application of identical reference numerals to the corresponding parts of the insert as illustrated in FIGS. 7 and 8. Furthermore, since the two parts 100 and 102 are identical, albeit differently positioned in their application to the insert 20, a description of one of them will suffice for the other.

Each part, for example, the part of FIG. 9, is in the form of an expanded polystyrene foam body, or a body which is constructed of any of the materials mentioned in connection with the displacement plug 22, and it includes a short cylindrical shank section 106 and an enlarged cylindrical head or pattern section 107. The shank 106 of the part .100 is adapted to be inserted downwardly in telescopic fashion into the helix 26 so that the head section .107 rests upon the upper end of the helix. The underneath annular shoulder which is established at the juncture between the shank section 106 and the head section 107 is shaped conformably to the shape of the upper end of the helix 22 in that it is provided with a helical ramp portion 110, terminating in a drop-off shoulder 108 which abuts against the free upper end 66 of the wire from which the helix is made. The lower part 102, being identical with the upper part 100, is provided with such a ramp portion 110 and shoulder 108, the shoulder abutting against the free lower end 58 of the wire from which the helix 66 is made, it being understood, of course, that the shank section 106 of the lower part 102 is telescopically received within the lower open end of the helix. The sections 107 of the parts 100 and .102 are referred to herein as pattern sections inasmuch as, during the pouring of the wet concrete into the concrete slab form, they create in the body of the concrete cylindrical clearance voids for facile entry of the pointed lag screw therethrough or thereinto. In the case of the upper part, the section 107 creates a cup in the upper surface of the slab leading to the interior of the helix. Although the polystyrene foam part 100 is left in position within this cup and within the helix when the lag screw is applied to the helix, the cup nevertheless is effective as a clearance void for penetration by the lag screw.

As shown in FIG. 8, when the two parts 100 and 102 are operatively installed within the helix 66, the opposed end faces of the shank sections 106 remain slightly spaced from each other to insure complete effective seating of the head portions 107 on the opposite ends, respectively, of the helix 66.

The operation of the composite displacement plug 100, 102 of FIGS. 7 to 10, inclusive, is similar to the opera tion of the composite displacement plug 22 previously described and it is deemed sufficient to state that, in the operation of the composite two-part displacement plug of FIGS. 7 to 10, inclusive, the lag screw 36 is threaded downwardly through the upper part 100 and passes through the lower part 102, thus forcing the material of both these parts outwardly against the inner wall surface of the helix 26. Obviously, since the longitudinal extent of the head section .107 of the lower part 1102 is appreciably less than the longitudinal extent of the lower cylindrical section :50 of the displacement plug 22, a lag screw will be employed which is sufficiently short that its lower end will not tend to project beyond the lower end of the part 102 or, in other words, which will terminate within the confines of the lower part.

The invention is not to be limited to the exact arrangement of parts shown in the accompanying drawings or described in this specification as various changes in the details of construction may be resorted to without departing from the spirit of the invention. Therefore, only insofar as the invention has particularly been pointed out in the accompanying claims is the same to be limited.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

1. As a new article of manufacture, an insert assembly adapted for embedment in a poured concrete slab and to form an anchor for a lag screw or the like, said assembly comprising an upstanding open-ended wire helix adapted to have the uper end thereof disposed directly inwards of, and opening onto, the top surface of the slab, the interior of the helix forming internal screw threads for receiving the shank portion of the lag screw, a wire leg structure Welded to the outer side of the helix for supporting the helix from a foundation surface for the slab at an elevated position thereabove, and a preformed displacement plug having an upper cylindrical portion substantially filling the helix for preventing entry of concrete into the helix during concrete pouring operations, and a lower cylindrical portion depending from the upper portion and extending below the helix for establishing a void in the poured concrete below the helix during such pouring operations, the diameter of said upper cylindrical portion being slightly greater than the minimum internal diameter of the helix so that said upper portion exists within the helix under slight compression, the diameter of the lower cylindrical portion being substantially equal to the overall diameter of the helix, said displacement plug being formed of a material having slight resistance to compressional forces and but slight tendency, after deformation, to return to its original size and shape, portions of said displacement plug being adapted to become displaced by forcible entry of the shank portion of the lag screw into and through the helix and compressed between said shank portion and the inside of the helix, and between said shank portion and the wall of said void, the juncture region between said upper and lower cylindrical portions of the displacement plug pre senting an upwardly facing shoulder shaped conformably to the shape of the lower end face of the helix and seating thereagainst coextensively.

2. As a new article of manufacture, an insert assembly adapted for embedment in a poured concrete slab and to form an anchor for a lag screw or the like, said assembly comprising an upstanding open-ended wire helix forming internal screw threads for receiving the shank portion of the lag screw, a wire leg structure welded to the outer side of and depending from the helix, a displacement plug having an upper cylindrical portion substantially filling and projecting above the helix for preventing entry of concrete into the helix during concrete pouring operations and a lower cylindrical portion depending from said upper portion and extending below the helix for establishing a void in the poured concrete below the helix during said concrete pouring operations, the diameter of said upper cylindrical portion being slight- 1y greater than the minimum internal diameter of the helix so that said upper portion exists within the helix under slight compression, the diameter of the lower cylindrical portion being substantially equal to the overall diameter of the helix, said displacement plug being formed of amaterial having slight resistance to compressional forces and but slight tendency, after deformation, to return to its original size and shape, portions of said displacement plug being adapted to become displaced by forcible entry of the shank portion of the lag screw into and through the helix and compressed between said shank portion and the inside of the helix, and between said shank portion and the wall of said void, and a cylindrical cup-shaped displacement cap formed of the same material as that of the displacement plug, said cap having an overall diameter substantially equal to the overall diameter of the helix and being telescopically received over the part of the displacement plug upper portion which projects above the helix, said cap being adapted to establish a void in the poured concrete above the helix, portions of the cap being adapted to become displaced by forcible passage of the shank portion of the lag screw therethrough.

3. As a new article of manufacture, an insert assembly adapted for embedment in a poured concrete slab and to form an anchor for a lag screw or the like, said assembly comprising an upstanding open-ended wire helix forming internal screw threads for receiving the shank portion of the lag screw, a Wire leg structure welded to the outer side of and depending from the helix, a displacement plug having an upper cylindrical portion substantially filling and projecting above the helix for pre venting entry of concrete into the helix during concrete pouring operations, and a lower cylindrical portion depending from the upper portion and extending below the helix for establishing a void in the poured concrete below the helix during such pouring operations, the diameter of said upper cylindrical portion being slightly greater than the minimum internal diameter of the helix so that said upper portion exists within the helix under slight compression, the diameter of the lower cylindrical portion being substantially equal to the overall diameter of the helix, said displacement plug being formed of a material having slight resistance to compressional forces and but slight tendency, after deformation, to return to its original size and shape, portions of said displacement plug being adapted to become displaced by forcible entry of the shank portion of the lag screw into and through the helix and compressed between said shank portion and the inside of the helix, and between said shank portion and the wall of said void, and a cylindrical cup-shaped displacement cap formed of the same material as that of the displacement plug, said cap having an overall diameter substantially equal to the overall diameter of the helix and being telescopically received over the part of the displacement plug upper portion which projects above the helix, said cap being adapted to establish a void in the poured concrete above the helix, portions of the cap being adapted to become displaced by forcible passage of the shank portion of the lag screw therethrough, the juncture region between the upper and lower cylindrical portions of the displacement plug presenting an upwardly facing shoulder shaped conformably to the shape of the lower end face of the helix and seating thereagainst coextensively, the lower rim of said cup-shaped displacement cap being shaped conformably to the shape of the upper end face of the helix and seating thereagainst coextensively.

4. The method of providing a fixed reaction anchor seat for a pointed lag screw in a body of concrete and of installing the lag screw in such anchor seat, said method comprising: inserting a preformed generally cylindrical plug of deformable material endwise into the central axial bore of an open-ended spiral wire-wound helix through one open end of the helix so as substantially to fill said bore while allowing a short section of the plug to project outwardly of the helix through said one open end, positioning said helix and the thus installed plug within a concrete body form, pouring a wet concrete mass into the form so as to cause the helix and its installed plug to become embedded in the wet concrete While confining the flow of the wet concrete in the form so that said short projecting section has its end face exposed at one surface of the poured concrete mass, allowing the concrete to become set, said preformed generally cylindrical plug being formed of a self-sustaining porous slightly resilient material possessing an appreciable degree of resistance to compressional forces yet being readily frangible when such forces exceed the elastic limit of the material, and thereafter threading the pointed lag screw endwise and centrally axially into said plug by a self-threading penetration process and causing the lag screw to crush and deform the material of the plug and force the same radially outwardly by a wedging action and into intimate contact with the wall of said bore so that the material of the plug is disintegrated and pressed hard against the undulatory internal wall of the bore.

5. The method of providing a fixed reaction anchor seat for a pointed lag screw in a body of concrete and of installing the lag screw in such seat, said method comprising: forcing by a sliding action a generally cylindrical plug of deformable material endwise and telescopically into the central axial bore of an open-ended spiral wire-wound helix through one open end thereof so as substantially to fill said bore while allowing a short section of the plug to project outwardly beyond said one open end, positioning said helix and the thus installed plug within a concrete body form, pouring a wet concrete mass into the form so as to cause the helix and its installed plug to become embedded in the wet concrete while confining the flow of the Wet concrete in the form so that said short projecting section has its end face exposed at one surface of the poured concrete mass, allowing the concrete to become set, said preformed cylindrical plug having a diameter slightly greater than the minimum diameter of said bore and being formed of a self-sustaining porous material possessing an appreciable degree of resistance to compressional forces so that when it is pushed endwise into the helix no deep internal molecular displacement will take place while a slight surface molecular displacement will result to conform the shape of the plug to the internal shape of the helix and thus fill the interstices between adjacent helix turns, and thereafter threading the pointed lag screw endwise and centrally axially into said plug by a self-threading penetration process and causing the lag screw to crush and deform the material of the plug and force the same radially outwardly by a wedging action and into intimate contact with the Wall of said bore so that the material of the plug is disintegrated and pressed hard against the undulatory internal wall of the bore.

6. As a new article of manufacture, an insert assembly adapted for embedment in a poured concrete body and to form an anchor for a pointed lag screw or the like, said assembly comprising an upstanding open-ended wire wound helix forming internal screw threads for receiving the shank portion of the lag :screw, a wire leg structure welded to the outer side of the helix and including a series of straight parallel wire leg sections which extend in the axial direction of the helix and overhang the lowermost convolution of the helix so as to provide an open cage structure below the helix when the latter is positioned vertically in a concrete body form, upper and lower displacement plugs for the upper and lower ends respectively of the helix, each plug being formed of a porous material possessing an appreciable degree of resistance to compressional force but being readily frangible under the influence of small internal molecular displacements, said upper plug including a lower cylindrical section telescopically received within the bore of the helix in tight frictional engagement with the internal threads thereof so that the surface region thereof is under compression and thus deformed in conformity with the internal thread pattern of the helix, and an upper cylindrical pattern section overlying the upper end of the helix and of a diameter approximating that of the maximum external diameter of the helix, said lower plug including an upper cylindrical section telescopically received within the bore of the helix in tight frictional engagement with the internal threads thereof so that the surface region thereof is under compression and thus deformed in conformity with the internal thread pattern of the helix, and a lower cylindrical pattern section underlying the lower end of the helix and existing in substantial tangential relationship with respect to the overhanging portions of said leg sections, said upper cylindrical pattern section of the upper plug being adapted to provide a cup-shaped depression in the upper surface of the hardened concrete body to facilitate endwise self-threading penetration of the upper and lower plugs by the pointed lag screw in the order named, the lower cylindrical pattern section of the lower plug being adapted to provide a cylindrical void in the hardened concrete body for reception of the pointed end of the lag screw when the latter has been fully threaded through the helix.

7. As a new article of manufacture, an insert assembly as set forth in claim 6 and wherein the juncture region between the cylindrical sections of each displacement plug presents a shoulder which is shaped conformably to the adjacent end face of the helix and abuts thereagainst coextensively.

8. As a new article of manufacture, an insert assembly adapted for embedment in a poured concrete body and to form an anchor for a pointed lag screw or the like, said assembly comprising an open-ended wire wound helix forming internal screw threads for receiving the shank portion of the lag screw, a wire leg structure welded to the outer side of the helix and including a series of straight parallel wire leg sections which extend in the axial direction of the helix and overhang the lowermost convolution of the helix so as to provide an open cage structure below the helix when the latter is positioned vertically in a concrete body form, and a displacement plug of generally cylindrical configuration disposed within the helix and substantially filling the same, portions of said displacement plug projecting axially outwardly from the opposite ends of the helix respectively and serving as patterns to establish voids in the poured concrete above and below the helix, said plug being formed of a material having the physical properties of expanded polystyrene form in that it is porous and self-sustaining, possesses appreciable resistance to compressional forces, and is frangible when subjected to compressional forces beyond its restorative power, said plug being adapted to remain in position within the helix during concrete pouring operations and to become embedded with the helix in the hardened concrete, to the end that it may be penetrated endwise by the pointed lag screw and the material thereof disintegrated under the internal compressional forces exerted thereon by the lag screw as the latter is threaded into the helix.

References Cited by the Examiner UNITED STATES PATENTS 1,365,718 1/21 Ogden --472 2,772,560 12/56 Neptune 50-517 2,794,336 6/57 Ballou 50472 2,880,608 4/59 Boll et a1. 50472 2,967,467 1/61 Maude 94-18.2

FRANK L. ABBOTT, Primary Examiner.

EARL J. WITMER, JACOB L. NACKENOFF,

Examiners. 

1. AS A NEW ARTICLE OF MANUFACTURE, AN INSERT ASSEMBLY ADAPTED FOR EMBEDMENT IN A POURED CONCRETE SLAB AND TO FORM AN ANCHOR FOR A LAG SCREW OR THE LIKE, SAID ASSEMBLY COMPRISING AN UPSTANDING OPEN-ENDED WIRE HELIX ADAPTED TO HAVE THE UPPER END THEREOF DISPOSED DIRECTLY INWARDS OF, AND OPENING ONTO, THE TOP SURFACE OF THE SLAB, THE INTERIOR OF THE HELIX FORMING INTERNAL SCREW THREADS FOR RECEIVING THE SHANK PORTION OF THE LAG SCREW, A WIRE LEG STRUCTURE WELDED TO THE OUTER SIDE OF THE HELIX FOR SUPPORTING THE HELIX FROM A FOUNDATION SURFACE FOR THE SLAB AT AN ELEVATED POSITION THEREABOVE, AND A PREFORMED DISPLACEMENT PLUG HAVING AN UPPER CYLINDICAL PORTION SUBSTANTIALLY FILLING THE HELIX FOR PREVENTING ENTRY OF CONCRETE INTO THE HELIX DURING CONCRETE POURING OPERATIONS, AND A LOWER CYLINDRICAL PORTION DEPENDING FROM THE UPPER PORTION AND EXTENDING BELOW THE HELIX FOR ESTABLISHING A VOID IN THE POURED CONCRETE BELOW THE HELIX DURING SUCH POURING OPERATIONS, THE DIAMETER OF SAID UPPER CYLINDRICAL PORTION BEING SLIGHTLY GREATER THAN THE MINIMUM INTERNAL DIAMETER OF THE HELIX SO THAT SAID UPPER PORTION EXISTS WITHIN THE HELIX UNDER SLIGHT COMPRESSION, THE DIAMETER OF THE LOWER CYLINDRICAL PORTION BEING SUB- 